Explosive.



' the explosive base unnecessarily high,

JESSE IB. BRONSTEIN, ALLENTOWN, PENNSYLVANIA.

Patented Apr. 4, .1911.

EXPLOSIVE.

988,858. Specification of Letters Patent. No Drawing'. Application filed November '22, 1909.

1 Serial No. 529,434.

To all whom "it may concern:

Be itknown that I, JESSE B. BRONSTEIN, a citizen of the United States, residing in Allentown, Pennsylvania, have invented certain Improvements in Explosives, of which the "following is a specification.

My invention relates to the manufacture of nitro starch blasting powders, and its object is'to improve POWClQI'L of this character by reducing their temperature of explosion.

Nitro starch powders as now on the market, consist of a mixture of nitro-st-arch, small percentages of a stabilizing agent; a suitable oxygen bearer, usually nitrate of soda; and other ingredients in small percentages, such, for example, as an oil for giving the desired consistency. These powders vary in grade from those containing approximately twenty per cent. (20%) by weight of the explosive base, up to those containing approximately sixty per cent. ((30%). In these powders as heretofore made,'there has existed a more or less considerable oxygen'excess, the effect of which is to render the temperature of explosion which is a disadvantage where the powder is used in gaseous coalmines. I have found that this oxygen excess may be materially decreased, and the temperature of explosion lowered without materially affecting the efficiency of the powder, by introducing into the mixture, to replace a portion of the oxygen' bearer, a reasonably large percentage of calcium carbonate in the crystalline form in which it is found in marble dust. The proportion of the calcium carbonate to such total aggregate of the mixture will, of course, vary according to the grade of the powder, and also to some extent according to the precise character of the other ingredients. I prefer to introduce the calcium carbonate in such amount as will leave just a slight excess of oxygen upon explosion, that is to say, such an amount as will cause the oxygen present to be slightly more than sufficient to oxidize all of the oxidizable elements to the highest degree of oxidation. this is that an oxygen deficiency results in the production of carbon monoxid which in some cases is considered objectionable. But as the production of carbon monoxid is in many cases permissible, and its presence does not in any way prevent the obtaining My reason for of my desired result, that is, the reduction of the temperature of explosion, it will be small percentages of understood that my-invention is not limited to the use of calcium carbonate in such proportion as will leave an oxygen excess.

I suggest the following as suitable proportions for obtaining a slight excess of oxygen, as I prefer, using for the purpose of illustration, a nitro starch powder containingnitro starch, a small percentage of a'stabilizing agent, nitrate of soda as the oxygen bearer, and a small percentage of oil to give consistency. In a powder of this character, of a 25% grade, that is, one in which the explosive base is approximately 25% by weight of the entire mixture, I have found that approximately d5% of marble dust and 30% ofthenitrate of soda, will produce the desired result. In a powder of grade, I have successfully used 35% of nitrate of soda and 30% of marble dust; in powder 35% of nitrate of soda and 20% of marble dust; and in a powder, 40% of nitrate of soda and 5% of marble dust. It will be understood, of course, that these figu i es are only approximate, as in each case allowance should be made for the added materials present in the powder. One skilled in the art will be able to readily ascertain by the use of chemical equation just what proportion of calcium carbonate should be used for any given powder to leave just a slight excess of oxygen, or to leave a greater excess, or

'obtain a deficiency of oxygen, if that be desired, but- I have given the foregoing illustrations as indicating what I have found in practice to be suitable proportions for my preferred purpose.

Vhile I prefer to use for my invention marble dust as wish to be limited to that, may be used to produce the prefer calcium carbonate in the form of marble dust not only because of its chemical and physical characteristics, including its relativelyhigh specific gravity and. hardness but also because it is cheap and readily obtainable. Other common mineral materials, however, which contain sufiicient amounts of calcium carbonate and have sufficient specific gravity and hardness to elfect the desired result may be used, as well as pulverized rock the purposes of stated, I do not as other agents same result. I

or earth materials having the required form and containing other carbonates, such for example as magnesium carbonate. terial employed. I have discovere l, slioul d not be soft but should be of a hardnessapproxi- The 1namating that of marble dust,'or-harder materials may be used.

As before stated, it 'will be understood that I do not-"wish to limit myself'to the use of the marble dust, or equivalent material, in any exact proportion, as my invention in its broader aspect involves broadly, the use of saidmaterials insuch proportions as will have the effect of reducing the temperature of explosion without rendering the powder inefiicient.

specified making up 10% to 70% of the added material of the powder can be successfully used e I claim:

1. A ni-tro-starch powder containing crystalline carbonate whose hardness and specific gravity are approximately those of marble dust added in such proportion as to reduce the temperature" of explosion in' substantially the manner set forth.

2. A .nitro-starch' powder containing a crystalline carbonate having approximately the physical properties of marble. dust added in such proportion as to leave but a slight oxygen excess upon explosion.

3. A nitro-starch powder containing nitrostarch and added material, ten per cent. to 70 per cent. by weight of said added material being a crystalline carbonate whose hardness and specific gravity are approximately those of marble dust.

4:. A nitro-starch powder containing a crystalline mineral material which has for its principal constituent a carbonate, and the hardness and specific gravity of which are approximately those of marble dust, said ma- Calcium carbonate in the form t'erial being added in such proportion as to reduce the temperature of explosion.

5. A nitro-starch powder contammg a crystalline mineral material which has'for its principal constituent a carbonate, and the hardness and specific gravit of which are approximately those of marb edust, said material being added in such proportion as to leave but a slight oxygen excess upon'explosion.

6. A nitro-starch powder containing nitrostarch and added material, 10 ercentto 7 0 per cent. by weight of said a ded material being a crystalline mineral material which has for its principal constituent a carbonate, and whose hardness-and specific gravity are ap roximately those of marble dust.

' A nitro-st-archpowder containing marble. dust added in such proportion as to reduce the temperature of explosion in subof two subscrib witnesses. ji s SE B. BRONSTEIN. WVitnesses CHARLES H. HowsoN,

WM. A. BARR.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. (1. 

